Heat pipe with fiber wick structure

ABSTRACT

A heat pipe with fiber wick structure includes a tubular body that is divided into an evaporator section, an adiabatic section and a condenser section, a mesh wick structure bonded to the inner wall of the tubular body to occupy the overall area of the evaporator section, a flat elongated fiber wick structure partially surrounded by the mesh wick structure in the tubular body and extending along the longitudinal axis of the tubular body to occupy a part of the inside space of the tubular body, and a working fluid filled in the tubular body. The fiber wick structure has one or multiple contact surfaces partially disposed in contact with and sintered to the mesh wick structure and partially disposed outside the mesh wick structure and disposed in contact with and sintered to the inner wall of the tubular body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to cooling technology and more particularly, to a heat pipe that has a fiber wick structure therein.

2. Description of the Related Art

Chinese Patent CN 201787845 U discloses a flat heat pipe having a complex wick structure. According to this design, the heat pipe comprises a tubular body, and a triple wick structure consisting of a trench-shaped wick layer, a porous wick layer and a fiber wick layer. This structure of heat pipe is functional before it is flattened or curved. However, when the heat pipe is flattened or curved, the porous wick layer (i.e., sintered copper powder wick structure can collapse, leading to reduced capillary force, poor working fluid backflow effect, poor thermal conductivity and poor thermal performance.

Sintered copper powder wick structures, mesh wick structures, metal fiber wick structures and trench-shaped wick structures are well known in the industry. However, there is currently no specific way of setting the difference between the sintered copper powder wick structures, the metal fiber wick structures or the mesh wick structures.

SUMMARY OF THE INVENTION

The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a heat pipe with fiber wick structure, which uses a fiber wick structure and a mesh wick structure instead of the use of a copper powder wick structure, preventing wick structure damage when the heat pipe is flattened or curved, ensuring the working fluid backflow effect and maintaining the overall thermal conductivity and thermal performance.

To achieve this and other objects of the present invention, a heat pipe comprises a tubular body, a mesh wick structure, a fiber wick structure and a working fluid. The tubular body is a flat, elongated, double closed-end container longitudinally divided into an evaporator section, an adiabatic section and a condenser section. The evaporator section and the condenser section are respectively located at two opposite ends of the tubular body. The adiabatic section is connected between the evaporator section and the condenser section. The mesh wick structure is mounted on an inner wall of the tubular body and covered over at least the overall inner surface area of the evaporator section of the tubular body. The fiber wick structure is formed of a collection of multiple fibers in a flat elongated shape, comprising at least one contact surface. The fiber wick structure is mounted in the evaporator section, the adiabatic section and the condenser section of the tubular body and extended along the longitudinal axis of the tubular body to occupy a part of the inside space of the tubular body. The working fluid is filled in the tubular body. Further, the mesh wick structure surrounds the fiber wick structure. The fiber wick structure has the at least one contact surface thereof partially disposed in contact with and sintered to the mesh wick structure and partially extended out of the mesh wick structure and disposed in contact with and sintered to the inner wall of the tubular body.

Subject to the arrangement of the fiber wick structure and the mesh wick structure, the fiber wick structure and the mesh wick structure will not be damaged when the tubular body is flattened or curved, ensuring the working fluid backflow effect and maintaining the overall thermal conductivity and thermal performance.

Other advantages and features of the present invention will be fully understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference signs denote like components of structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an oblique top elevational view of heat pipe with fiber wick structure in accordance with a first embodiment of the present invention.

FIG. 2 is a front view of the heat pipe with fiber wick structure in accordance with the first embodiment of the present invention.

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2.

FIG. 5 is a sectional view of heat pipe with fiber wick structure in accordance with a second embodiment of the present invention.

FIG. 6 is a sectional view of heat pipe with fiber wick structure in accordance with a third embodiment of the present invention.

FIG. 7 is a sectional view of heat pipe with fiber wick structure in accordance with a fourth embodiment of the present invention, where the view angle is similar to FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-4, a heat pipe with fiber wick structure 10 in accordance with a first embodiment of the present invention is shown. The heat pipe 10 comprises a tubular body 11, a mesh wick structure 13, a fiber wick structure 15 and a working fluid.

The tubular body 11 is a flat, elongated, double closed-end container. Further, the tubular body 11 is longitudinally divided into three parts: the evaporator section H, the adiabatic (transport) section A and the condenser section C. The evaporator section H and the condenser section C are respectively located at the two opposite ends of the tubular body 11.

The mesh wick structure 13 is arranged on an inner wall of the tubular body 11, covering at least the overall inner surface area of the evaporator section H of the tubular body 11. In the present first embodiment, the mesh wick structure 13 is sintered to the inner wall of the tubular body 11 to cover the overall inner surface area of the evaporator section H. The mesh wick structure 13 increases the heating surface area and water storage capacity of the evaporator section H, and also enhances the capillary force of the evaporator section H on the working fluid.

The fiber wick structure 15 is formed of a collection of multiple fibers and arranged to exhibit a flat elongated shape, having two contact surfaces 16 respectively located on opposing top and bottom sides thereof. The fiber wick structure 15 is longitudinally mounted in the evaporator section H, adiabatic (transport) section A and condenser section C of the tubular body 11 on the middle, and extended along the longitudinal axis of the tubular body 11. The two contact surfaces 16 of the fiber wick structure 15 are bonded to the inner wall of the tubular body 11. Thus, the fiber wick structure 15 occupies a part of the inside space of the tubular body 11, dividing the inside space of the tubular body 11 into two subspaces 17. In the present first embodiment, the fiber wick structure 15 is formed of a bundle of multiple metal fibers.

The working fluid is filled into the tubular body 11. Further, the working fluid is absorbed into the mesh wick structure 13 and the fiber wick structure 15, and thus, it is difficult to indicate the working fluid on the drawings. Further, because the working fluid is a very familiar component in the heat pipe industry, it is not illustrated in the annexed drawings.

After understood the architecture of the first embodiment, the application of this first embodiment is explained hereinafter.

As illustrated in FIG. 4, the evaporator section H of the tubular body 11 is disposed in contact with a heat source (not shown) to absorb heat energy from the heat source, enabling the working fluid to be heated and evaporated in the evaporator section H so that the working fluid vapor thus produced can be transferred through the two subspaces 17 to the condenser section C. Because the condenser section C does not receive any external thermal energy, the working fluid vapor in the condenser section C is condensed into liquid phase that permeates into the fiber wick structure 15 and flows back to the evaporator section H for further evaporation. This gas-liquid transition is repeated again and again, achieving rapid thermal conductivity and the effect of uniform temperature.

Subject to the arrangement of the fiber wick structure 15 and the mesh wick structure 13 in the aforesaid first embodiment of the present invention instead of the use of a copper powder wick structure that can collapse when the heat pipe is flattened or deformed, the wick structures of the heat pipe in accordance with the present invention will not be damaged when the tubular body 11 is flattened or curved, ensuring the working fluid backflow effect and maintaining the overall thermal conductivity or thermal performance.

It is well known in the industry that the higher the void fraction of the wick structure, the lower the capillary action. The maximum heat transfer capacity (Qmax) can be obtained when the void fraction of the wick structure is in a certain range. Therefore, the use of the fiber wick structure 15 and the mesh wick structure 13 prevents collapsing or increasing the void fraction of the wick structure when the tubular body 11 is flattened or curved, ensuring the maximum heat transfer capacity.

Referring to FIG. 5, a heat pipe with fiber wick structure 10′ in accordance with a second embodiment of the present invention is shown. This second embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The mesh wick structure 13′ covers the overall inner surface area of the evaporator section H of the tubular body 11′ and a part of the adiabatic (transport) section A.

When compared with the aforesaid first embodiment, the length of the mesh wick structure 13′ in accordance with this second embodiment is relatively longer than the mesh wick structure 13 in accordance with the first embodiment of the present invention, providing a relatively longer return path for the working fluid that is condensed on the inner wall of the tubular body 11′,

However, due to that the mesh wick structure 13′ occupies a part of the volume of the two subspaces 17′, the flow path for the working fluid is relatively narrower in this second embodiment. Thus, the user can decide whether or not to adopt the configuration of the second embodiment according to actual requirements.

The other structural features of this second embodiment and the effect this second embodiment can achieve are same as the aforesaid first embodiment, so we will not repeat them there.

Referring to FIG. 6, a heat pipe with fiber wick structure 10″ in accordance with a third embodiment of the present invention is shown. This third embodiment is substantially similar to the aforesaid second embodiment with the exceptions as follows:

The mesh wick structure 13″ covers the overall inner surface of the evaporator section H of the tubular body 11″ and the overall inner surface of the adiabatic (transport) section A.

When compared with the aforesaid second embodiment, the length of the mesh wick structure 13″ in accordance with this third embodiment is relatively longer than the mesh wick structure 13′ in accordance with the second embodiment of the present invention, providing a relatively more longer return path for the working fluid, however, due to that the mesh wick structure 13″ occupies more volume of the two subspaces 17″, the flow path for the working fluid is relatively narrower in this third embodiment. Thus, the user can decide whether or not to adopt the configuration of the third embodiment according to actual requirements.

The other structural features of this third embodiment and the effect this third embodiment can achieve are same as the aforesaid first embodiment, so we will not repeat them there.

Referring to FIG. 7, a heat pipe with fiber wick structure 40 in accordance with a fourth embodiment of the present invention is shown. This fourth embodiment is substantially similar to the aforesaid first embodiment with the exceptions as follows:

The fiber wick structure 45 is so arranged that one contact surface 46 of the fiber wick structure 45 is bonded to the inner wall of the tubular body 41, and the other contact surface 46 of the fiber wick structure 45 is spaced from the inner wall of the tubular body 41 at a predetermined distance. Thus, the fiber wick structure 45 simply occupies a part of the inside space of the tubular body 41 without dividing the inside space of the tubular body 41 into two opposing subspaces.

The other structural features of this fourth embodiment and the effect this third embodiment can achieve are same as the aforesaid first embodiment, so we will not repeat them there.

Further, it's worth mentioning that the arrangement of the fiber wick structure 15(45) on the central axis of the tubular body 11(41) in the aforesaid four embodiments is not a limitation. Alternatively, the fiber wick structure 15(45) can be arranged on one lateral side of the central axis of the tubular body 11(41), achieving the same effects. 

What is claimed is:
 1. A heat pipe, comprising: a tubular body being a flat, elongated, double closed-end container longitudinally divided into an evaporator section, an adiabatic section and a condenser section, said evaporator section and said condenser section being respectively located at two opposite ends of said tubular body, said adiabatic section being connected between said evaporator section and said condenser section; a mesh wick structure mounted on an inner wall of said tubular body and covering at least the overall inner surface area of said evaporator section of said tubular body; a fiber wick structure formed of a collection of multiple fibers in a flat elongated shape and comprising at least one contact surface, said fiber wick structure being mounted in said evaporator section, said adiabatic section and said condenser section of said tubular body and extending along a longitudinal axis of said tubular body to occupy a part of the inside space of said tubular body; and a working fluid filled in said tubular body; wherein said mesh wick structure surrounds said fiber wick structure, said fiber wick structure having the said at least one contact surface thereof partially disposed in contact with and sintered to said mesh wick structure and partially extended out of said mesh wick structure and disposed in contact with and sintered to the said inner wall of said tubular body.
 2. The heat pipe as claimed in claim 1, wherein said mesh wick structure occupies the overall space of said evaporator section and a part of said adiabatic section.
 3. The heat pipe as claimed in claim 1, wherein said mesh wick structure occupies the overall space of said evaporator section and the overall space of said adiabatic section.
 4. The heat pipe as claimed in claim 1, wherein said fiber wick structure is formed of a bundle of multiple metal fibers. 